Cells: Add support for compute HostAPI()

This will allow the hosts API extension to work. Calls to get service
information from the DB are proxied via cells.

When using the host extension, the 'id' and 'host' fields for
service/compute will be modified to have the cell prepended to it.  One
can do a 'show' on a 'path!to!cell@id' to see details for a particular
host in the 'path!to!cell' cell, for instance.

Implements bp/nova-compute-cells

Change-Id: I8137fa64d2578acfc3d2457c231de2b0d69b96d8
Adds original copyright notice to refactored files

Fixes bug: #1116586

The Hyper-V driver contributed for Folsom contains some refactored code
from the Diablo release contributed by Cloud.com.

Although the copyright notice remained in the "driver.py" file, it has
erroneously not been added to the new "vmops.py" and "vmutils.py" files
that contained some refactored code from the original contribution.

Change-Id: I71cf1df30c0b2ef5ae3df38f3c6f0311b7b4b3d9
Merge "Cells: Add support for compute HostAPI()"
Merge "Adds original copyright notice to refactored files"